gary_wong5 Posted May 20, 2009 Report Share Posted May 20, 2009 Please excuse my ignorant and backward. I acquired a pair of AR-7s' yesterday, but have no idea how to connect them to amplifier. They show "1" and "2" and, there is a switch for "NORMAL" and "FLAT"."1" is to "negative", "2" for "positive"? What is the right setting for the switch for normal listening? Link to comment Share on other sites More sharing options...
genek Posted May 20, 2009 Report Share Posted May 20, 2009 "1" is to "negative", "2" for "positive"? What is the right setting for the switch for normal listening?"1" is positive and "2" negative, but it really doesn't matter as long as both channels are wired the same.The correct switch setting is the one you like best. Link to comment Share on other sites More sharing options...
gary_wong5 Posted May 20, 2009 Author Report Share Posted May 20, 2009 "1" is positive and "2" negative, but it really doesn't matter as long as both channels are wired the same.The correct switch setting is the one you like best.Thanks. I have this same question when connecting my Advent/1, but the "0" is negative and "1" is positive. So interesting it is when dealing with vintage speakers. I like the switch setting at "NORMAL".By the way, these little AR-7s' sound more natural and dynamic than my AR98LS when A-B side by side. Just amazing. No wonder many of us prefer original AR models. Link to comment Share on other sites More sharing options...
Robert_S Posted May 20, 2009 Report Share Posted May 20, 2009 "1" is to "negative", "2" for "positive"?Hello,The quote below is from the enclosed AR-7 System Assembly drawing (see Note 3):"Phase will be such that a positive DC potential to the terminal marked 2 will cause the woofer cone to move away from the system."According to my understanding, this would imply, strictly speaking, that (as you say) terminal 1 is for negative and terminal 2 is for positive. (It is simple to check this using an AA battery, or similar.)Of course, given that 'absolute phase' may vary from recording to recording, and can sometimes be all-over-the-place within the same recording, I agree that it may not matter that much. I guess it depends on the belief systems at play!Robert_S Link to comment Share on other sites More sharing options...
gary_wong5 Posted May 20, 2009 Author Report Share Posted May 20, 2009 Why the speaker's phases were not standardized (0, 1 and 2 are confused) or stated clearly as simple as "+" and "-" as today? Link to comment Share on other sites More sharing options...
gary_wong5 Posted May 20, 2009 Author Report Share Posted May 20, 2009 Hello,The quote below is from the enclosed AR-7 System Assembly drawing (see Note 3):"Phase will be such that a positive DC potential to the terminal marked 2 will cause the woofer cone to move away from the system."According to my understanding, this would imply, strictly speaking, that (as you say) terminal 1 is for negative and terminal 2 is for positive. (It is simple to check this using an AA battery, or similar.)Of course, given that 'absolute phase' may vary from recording to recording, and can sometimes be all-over-the-place within the same recording, I agree that it may not matter that much. I guess it depends on the belief systems at play!Robert_SI checked and confirmed that "2" is positive by following your advice.Actually, I connected positive to "1" when receiving those speakers. After confirmation, I changed to "2". Wow, they now sound widely open, strong bass and vocal is centre. Conclusion:SPEAKER PHASING IS ABSOLUTELY IMPORTANT.Thank you Robert. Link to comment Share on other sites More sharing options...
genek Posted May 20, 2009 Report Share Posted May 20, 2009 I checked and confirmed that "2" is positive by following your advice.Actually, I connected positive to "1" when receiving those speakers. After confirmation, I changed to "2". Wow, they now sound widely open, strong bass and vocal is centre. Conclusion:SPEAKER PHASING IS ABSOLUTELY IMPORTANT."Speaker phasing" refers to the relative phases of multiple speakers, not to the polarity of a single speaker. IOW, whether all the speakers match.The instructions for my older AR-2ax say "when connecting the loudspeakers for a stereo system, the polarity of both speakers must be the same." Amplifiers of the period in which classic ARs were originally designed (50's-60's) were often not consistently marked between different brands, and were often marked "0" and "1," rather than "+" and "-." This is especially common on older mono amplifiers. WRT the drawing instructions for assembly testing using a DC potential, keep in mind that audio signals are AC and have no polarity. The DC test method was a means of ensuring consistent assembly using drivers that sometimes didn't come marked for polarity from their vendors.If switching polarities makes a difference you can hear, it is possible that one of the drivers in one of the speakers is wired incorrectly. Have yours been repaired or restored in any way? Link to comment Share on other sites More sharing options...
gary_wong5 Posted May 20, 2009 Author Report Share Posted May 20, 2009 "Speaker phasing" refers to the relative phases of multiple speakers, not to the polarity of a single speaker. IOW, whether all the speakers match.The instructions for my older AR-2ax say "when connecting the loudspeakers for a stereo system, the polarity of both speakers must be the same." Amplifiers of the period in which classic ARs were originally designed (50's-60's) were often not consistently marked between different brands, and were often marked "0" and "1," rather than "+" and "-." This is especially common on older mono amplifiers. WRT the drawing instructions for assembly testing using a DC potential, keep in mind that audio signals are AC and have no polarity. The DC test method was a means of ensuring consistent assembly using drivers that sometimes didn't come marked for polarity from their vendors.If switching polarities makes a difference you can hear, it is possible that one of the drivers in one of the speakers is wired incorrectly. Have yours been repaired or restored in any way?Just refoam has been done so far. I opened up the woofer, internal glass fibre looks just intact to me. Link to comment Share on other sites More sharing options...
genek Posted May 20, 2009 Report Share Posted May 20, 2009 Just refoam has been done so far. I opened up the woofer, internal glass fibre looks just intact to me.The woofers would have had to be removed to be refoamed. You'll want to check to see that they were reinstalled correctly. There's no AR-7 schematic in the library, but the convention in those days was red wire to + and blue wire to - (if the woofer's terminals are not marked, this is where you'll want to do the battery test on the woofer). Link to comment Share on other sites More sharing options...
AR_nut_in_Oregon Posted May 20, 2009 Report Share Posted May 20, 2009 quote genek:"There's no AR-7 schematic in the library, but the convention in those days was red wire to + and blue wire to - ...."Here is a Connection Diagram (schematic) which I developed from 2 different pairs of AR-7s...as noted on my drawing, the earlier serial numbers had "front-wired" tweets.Hope this helps...AR_7_Connection_Diagram.pdf Link to comment Share on other sites More sharing options...
genek Posted May 20, 2009 Report Share Posted May 20, 2009 quote genek:"There's no AR-7 schematic in the library, but the convention in those days was red wire to + and blue wire to - ...."Here is a Connection Diagram (schematic) which I developed from 2 different pairs of AR-7s...as noted on my drawing, the earlier serial numbers had "front-wired" tweets.Hope this helps...It appears from this that "1" really is negative. I guess I'll have to switch my speaker leads around someday and see if I can hear a difference. Link to comment Share on other sites More sharing options...
AR_nut_in_Oregon Posted May 21, 2009 Report Share Posted May 21, 2009 It appears from this that "1" really is negative. I guess I'll have to switch my speaker leads around someday and see if I can hear a difference. genek:You made me re-check the connections (no problem)...Here is a pic of the "Front Wired Tweets" from the inside...And, here is a pic of the Terminals from the back...Note that the "Front Wired Tweets" version has the Terminals arranged in a "Horizontal" orientation, rather than the "Vertical" orientation as shown in the "Assembly Drawing" attached earlier.Next, see that the Terminals on the "Back Wired Tweets" version are arranged in a "Vertical" orientation as indicated in the "Assembly Drawing"...So, I wonder when that change was made? But, the polarity (by number) does seem to hold true for the "Classic" models such as: AR-2ax, AR-5, etc. in that number "1" has been consistantly "negative" and number "2" has been consistantly, "positive". Link to comment Share on other sites More sharing options...
gary_wong5 Posted May 21, 2009 Author Report Share Posted May 21, 2009 There is a red colour sticker marked "+" shown on rear woofer magnet. Red cable is connected to "+", woofer cone move away from system when conducting DC voltage test. So, "2" should be positive.My speakers might be the later version (1974) as shown on label, walnut grained vinyl, brownish grille cover and vertical array "1" and "2". Link to comment Share on other sites More sharing options...
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